This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In the first study of poly(IC) and rectal SIV transmission, we asked whether TLR ligation by poly(IC) could prevent SIV transmission or modify the course of infection in animals that were not protected. Poly(IC) was applied to the rectal epithelium of macaques either coincident with (n=7) or 24 hours prior to (n=7) SIVwt challenge. As controls, we challenged 4 animals with SIVwt without receiving poly(IC) treatment and included the 4 animals used to test the infectivity of the virus stock (n=8 total). It does not appear that either the coincident or the 24 h pre-treatment with poly(IC) affected the infection rate (coincident: 4 of 7 infected, 57%;24 h pre: 4 of 7 infected, 57%, control: 6 of 8 infected, 75%). However, we are continuing to evaluate differences in plasma virus RNA over time (at peak and set point) as well as innate and adaptive immune parameters (memory and na[unreadable]ve T cell subsets, regulatory T cells, antibodies, DCs and the ratio of myeloid and plasmacytoid DCs, and cytokine and chemokine production) in these 18 animals.